Almost 230,000 unionized U.S. Postal Service workers will receive a $937 annual cost-of-living adjustment next month, according to a USPS spokeswoman.

The increase, covering about 162,000 employees represented by the American Postal Workers Union and another 66,000 represented by the National Rural Letter Carriers’ Association, takes effect Sept. 7, Patricia Licata said in an email Tuesday.

The contractually required COLAs come after a 1 percent general wage increase last November that followed a two-year freeze, Licata said, adding that these are the only increases for postal employees for fiscal 2013, which ends next month.

In fiscal 2014, however, workers represented by the National Postal Mail Handlers Union are scheduled for a 1 percent increase in November, and members of the National Association of Letter Carriers bargaining unit will receive two cost-of-living adjustments totaling $687 next year, according to the union.

Employees represented by the NALC received no such adjustments this year or in 2012, President Fredric Rolando said in an emailed statement. APWU-represented workers will also receive a 1.5 percent pay boost in November, union spokeswoman Sally Davidow said.